Query Consolidation: Interpreting a Set of Independent Queries Using a Multidatabase Architecture in the Reverse Direction
Aybar C. Acar, Amihai Motro · 2008
Abstract. We introduce the problem of query consolidation, which seeks to interpret a set of disparate queries submitted to independent data-bases with a single “global ” query. This problem has multiple applica-tions, from improving database design to protecting information from a seemingly innocuous set of apparently unrelated queries. The problem exhibits attractive duality with the much-researched problem of query decomposition, which has been addressed intensively in the context of multidatabase environments: How to decompose a query submitted to a virtual database into a set of local queries that are evaluated in individ-ual databases. We set the new problem in the architecture of a canonical multidatabase system, using it in the “reverse direction”. The process in-corporates two steps where multiplicity of solutions must be considered: At one point the system must infer the most likely set of equi-joins for a set of relations; at another point it must discover the most likely selection constraints that would be applied to a relation. In each case we develop a procedure that ranks solutions according to their perceived likelihood. The final result is therefore a ranked list of suggested consolidations. 1